The subject matter disclosed herein generally relates to pneumatic actuators and, more particularly, to improved piston ring sealing for pneumatic actuators.
High temperature pneumatic valves often use piston rings for sealing. Due to friction and acceleration forces acting on the piston ring, it can be difficult to maintain a sufficient axial force margin to keep the piston ring loaded against a sealing surface of the piston. If the seal is not maintained, air may leak through and/or around the piston ring. Small amounts of intermittent air leakage across the piston ring can lead to control instabilities.